Phase current commutation in electric motors is typically accomplished by feeding back a rotor position signal to a controller from a shaft angle transducer, e.g. an encoder or a resolver. To improve reliability and to reduce size, weight, inertia and cost in electric motor drives, however, it is desirable to eliminate the shaft angle transducer. In a switched reluctance motor drive, for example, methods for indirectly determining rotor position without using a shaft angle transducer have been described in U.S. Pat. No. 5,097,190 of J. P. Lyons and S. R. MacMinn, and U.S. Pat. No. 5,107,195 of J. P. Lyons, M. A. Preston and S. R. MacMinn, both assigned to the instant assignee. Measurements from indirect rotor position sensors may be noisy and, in general, are not continuously available. In particular, measurements are available only at discrete instants in time as dictated by microprocessor sampling and calculation requirements which will not, in general, coincide with the desired commutation times for the electric machine. Therefore, it is necessary to process and translate such noisy position measurements into reliable phase current commutation times occurring at the appropriate instants.